Efficient phototrophic production of a high-value sesquiterpenoid from the eukaryotic microalga Chlamydomonas reinhardtii.

The heterologous expression of terpene synthases in microbial hosts has opened numerous possibilities for bioproduction of desirable metabolites. Photosynthetic microbial hosts present a sustainable alternative to traditional fermentative systems, using freely available (sun)light and carbon dioxide as inputs for bio-production. Here, we report the expression of a patchoulol synthase from Pogostemon cablin Benth in the model green microalga Chlamydomonas reinhardtii. The sesquiterpenoid patchoulol was produced from the alga and was used as a marker of sesquiterpenoid production capacity. A novel strategy for gene loading was employed and patchoulol was produced up to 922±242µgg CDW in six days. We additionally investigated the effect of carbon source on sesquiterpenoid productivity from C. reinhardtii in scale-up batch cultivations. It was determined that up to 1.03mgL sesquiterpenoid products could be produced in completely photoautotrophic conditions and that the alga exhibited altered sesquiterpenoid production metabolism related to carbon source.